Aloe emodin is an anthraquinone compound found naturally in aloe vera plants and other plants such as rhubarb. It can be isolated from aloe sap through refluxing with hydrochloric acid and ferric chloride, followed by extraction with toluene. Identification and quantification of aloe emodin can be done using techniques such as thin layer chromatography and HPLC. Aloe emodin has various pharmacological effects including anticancer and anti-inflammatory properties, but also potential hepatotoxicity and nephrotoxicity. It is used as a laxative but may also help suppress breast cancer cell proliferation.

1. Aloe emodin
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2. 3D Model

3. Introduction
Other name – Rhabarberone , 3-Hydroxymethylchrysazin
Aloe emodin is an anthraquinone and an isomer of emodin present in aloe latex, an exudate
from the aloe plant.
Aloe emodin is an orange colored anthraquinone obtained from chemical modification of
barbaloin. Aloes which is used as a purgative is a rich source of barbaloin.
Aloe emodin also occurs naturally in small concentration in the free state and as a glycoside in
rhizomes of Rheum emodi L. (Family- Polygonaceae), Frangula alnus Mill., Frangula purshina
(DC.) Cooper (Family -.Rhamnaceae),etc.
Aloes is the dried latex of leaves of Aloe vera (L.) Burm.f., Aloe perryi Baker (Family-
Asphodelaceae ).

4. Physical Properties
❑Formula - C15H10O5
❑Melting point - 223 to 224 °C (433 to 435 °F) Sublimes in CO2
stream
❑IUPAC Name - 1,8-Dihydroxy-3-(hydroxymethyl)-9,10-
anthracenedione
❑Molar mass - 270.240 g·mol−1
❑Solubility – Freely soluble in hot alcohol , toluene , ether , benzene with
yellow colour , ammonia water and sulphuric acid with crimson color ,
insoluble in water
❑Therapeutic category – Cathartic

5. Biological source
❑Aloe emodin is found in the gel, sap or leaves of aloe vera, the socotrine aloe, Barbados aloe,
and Zanzibar aloes, the bark of Frangula (Rhamnus frangula) and cascara sagrada (Rhamnus
purshiana), the leaves of Senna (Cassia angustifolia), and the rhizome of rhubarb (Rheum
rhaponticum).
❑Aloe-emodin has not been found in Natal aloes

6. Isolation & Characterization Aloe emodin
from Aloe sap.
Requirements – Aloes, hydrochloric acid , ferric chloride , toluene, Soxhlet apparatus;
time required : 4 hours
Procedure – Transfer 50 gm of aloe powder to 2 litre round bottom flask.
Add 300 ml hydrochloric acid followed by 160 gm of ferric chloride dissolved in 675 ml water .
Reflux the content for 4 hours .
Black colour residue forms . Allow the content to cool , filter the residue and wash with water
using Buchner funnel .
Dry the residue and extract with 300 ml of toluene using Soxhlet apparatus .
Concentrate the toluene extract .
On cooling , aloe emodin separates out ( yield about 3 gm)

7. Identification of Aloe emodin by
Thin layer chromatography (TLC)
Preparation of sample – Transfer 1 gm of powdered aloes in a test tube , add 5 ml methanol &
shake to mix thoroughly for 2-3 min and then allow the contents to settle. Remove the methanol
solution from undissolved solids using pipette or by decantation . Use this solution for
development of TLC.
Preparation of Aloe emodin solution: Prepare 0.01% solution of Aloe emodin in methanol and
use this solution for development of TLC.
Solvent system: Ethyl acetate: Methanol: Water (100:13.5:10);
detection: 5% potassium hydroxide solution in alcohol.

8. HPLC analysis by Aloe Emodin
Preparation of sample – Dissolve about 10 mg of Aloe emodin in methanol in a 10-ml
volumetric flask and make up the volume. Prepare test solution of 100 μg / mg by suitable
dilution of stock solution .
Chromatographic conditions: –
Column – Purospher , RP-18e
Detection – UV- 254 nm
Mobile phase – Methanol : water containing 0.05% o-phosphoric acid (90:10)
Flow rate – 1ml/min
Injection volume – 20μl
Run time – 10 min ( tR 5 min approx.)

11. Pharmacological effects
❑Emerging evidence suggests that aloe-emodin exhibits many pharmacological effects, including
anticancer, antivirus, anti-inflammatory, antibacterial, antiparasitic, neuroprotective, and
hepatoprotective activities.
❑These pharmacological properties lay the foundation for the treatment of various diseases,
including influenza virus, inflammation, sepsis, Alzheimer's disease, glaucoma, malaria, liver
fibrosis, psoriasis, Type 2 diabetes, growth disorders, and several types of cancers.
❑However, an increasing number of published studies have reported adverse effects of aloe-
emodin. The primary toxicity among these reports is hepatotoxicity and nephrotoxicity, which
are of wide concern worldwide.
❑Pharmacokinetic studies have demonstrated that aloe-emodin has a poor intestinal absorption,
short elimination half-life, and low bioavailability.

12. Uses
❑It has a strong stimulant-laxative action.
❑Aloe emodin is not carcinogenic when applied to the skin, although it may increase the
carcinogenicity of some kind of radiation.
❑Aloe emodin had a pronounced anti-proliferative effect in Merkel carcinoma cells, a highly
aggressive and resistant cell line, and it potentiated the anti-proliferative effect of
chemotherapeutic agents such as cisplatin, doxorubicin, and 5–fluoroucil.
❑Emodin and Aloe-Emodin Suppress Breast Cancer Cell Proliferation through ERα Inhibition

13. References
https://en.wikipedia.org/wiki/Aloe_emodin
https://chemapps.stolaf.edu/jmol/jmol.php?model=O%3DC2c1cccc%28O%29c1C%28%3DO%29c3c2c
c%28cc3O%29CO
https://pubmed.ncbi.nlm.nih.gov/31680350/
https://www.sciencedirect.com/topics/chemistry/aloe-emodin
https://www.researchgate.net/publication/324821381_Estimation_of_Aloe-
emodin_Content_in_Cassia_grandis_and_Cassia_garrettiana_Leaves_Using_TLC_Densitometric_Met
hod_and_TLC_Image_Analysis
https://www.researchgate.net/publication/255757528_Simultaneous_determination_of_aloin_A_an
d_aloe_emodin_in_products_containing_Aloe_vera_by_ultra-
performance_liquid_chromatography_with_tandem_mass_spectrometry
https://www.scirp.org/html/6-2200518_38267.htm